Time handling overhaul

Terminology cleanup: the type "Ticks" has been renamed "Time", which
is an StgWord64 in units of TIME_RESOLUTION (currently nanoseconds).
The terminology "tick" is now used consistently to mean the interval
between timer signals.

The ticker now always ticks in realtime (actually CLOCK_MONOTONIC if
we have it).  Before it used CPU time in the non-threaded RTS and
realtime in the threaded RTS, but I've discovered that the CPU timer
has terrible resolution (at least on Linux) and isn't much use for
profiling.  So now we always use realtime.  This should also fix

The default tick interval is now 10ms, except when profiling where we
drop it to 1ms.  This gives more accurate profiles without affecting
runtime too much (<1%).

Lots of cleanups - the resolution of Time is now in one place
only (Rts.h) rather than having calculations that depend on the
resolution scattered all over the RTS.  I hope I found them all.

1 files changed, 17 insertions, 21 deletions

diff --git a/rts/posix/GetTime.c b/rts/posix/GetTime.c
index eab7177fe5..c31b319af4 100644
--- a/rts/posix/GetTime.c
+++ b/rts/posix/GetTime.c
@@ -44,7 +44,7 @@
 // we'll implement getProcessCPUTime() and getProcessElapsedTime()
 // separately, using getrusage() and gettimeofday() respectively
 
-Ticks getProcessCPUTime(void)
+Time getProcessCPUTime(void)
 {
 #if !defined(BE_CONSERVATIVE) && defined(HAVE_CLOCK_GETTIME) && defined (_SC_CPUTIME) && defined(CLOCK_PROCESS_CPUTIME_ID) && defined(HAVE_SYSCONF)
     static int checked_sysconf = 0;
@@ -59,8 +59,7 @@ Ticks getProcessCPUTime(void)
         int res;
         res = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
         if (res == 0) {
-            return ((Ticks)ts.tv_sec * TICKS_PER_SECOND +
-                    ((Ticks)ts.tv_nsec * TICKS_PER_SECOND) / 1000000000);
+            return SecondsToTime(ts.tv_sec) + NSToTime(ts.tv_nsec);
         }
     }
 #endif
@@ -69,20 +68,18 @@ Ticks getProcessCPUTime(void)
     {
         struct rusage t;
         getrusage(RUSAGE_SELF, &t);
-        return ((Ticks)t.ru_utime.tv_sec * TICKS_PER_SECOND +
-                ((Ticks)t.ru_utime.tv_usec * TICKS_PER_SECOND)/1000000);
+        return SecondsToTime(t.ru_utime.tv_sec) + USToTime(t.ru_utime.tv_usec);
     }
 }
 
-Ticks getProcessElapsedTime(void)
+Time getProcessElapsedTime(void)
 {
     struct timeval tv;
     gettimeofday(&tv, (struct timezone *) NULL);
-    return ((Ticks)tv.tv_sec * TICKS_PER_SECOND +
-	    ((Ticks)tv.tv_usec * TICKS_PER_SECOND)/1000000);
+    return SecondsToTime(tv.tv_sec) + USToTime(tv.tv_usec);
 }
 
-void getProcessTimes(Ticks *user, Ticks *elapsed)
+void getProcessTimes(Time *user, Time *elapsed)
 {
     *user    = getProcessCPUTime();
     *elapsed = getProcessElapsedTime();
@@ -92,29 +89,29 @@ void getProcessTimes(Ticks *user, Ticks *elapsed)
 
 // we'll use the old times() API.
 
-Ticks getProcessCPUTime(void)
+Time getProcessCPUTime(void)
 {
 #if !defined(THREADED_RTS) && USE_PAPI
     long long usec;
     if ((usec = PAPI_get_virt_usec()) < 0) {
 	barf("PAPI_get_virt_usec: %lld", usec);
     }
-    return ((usec * TICKS_PER_SECOND) / 1000000);
+    return USToTime(usec);
 #else
-    Ticks user, elapsed;
+    Time user, elapsed;
     getProcessTimes(&user,&elapsed);
     return user;
 #endif
 }
 
-Ticks getProcessElapsedTime(void)
+Time getProcessElapsedTime(void)
 {
-    Ticks user, elapsed;
+    Time user, elapsed;
     getProcessTimes(&user,&elapsed);
     return elapsed;
 }
 
-void getProcessTimes(Ticks *user, Ticks *elapsed)
+void getProcessTimes(Time *user, Time *elapsed)
 {
     static nat ClockFreq = 0;
 
@@ -141,20 +138,20 @@ void getProcessTimes(Ticks *user, Ticks *elapsed)
 
     struct tms t;
     clock_t r = times(&t);
-    *user = (((Ticks)t.tms_utime * TICKS_PER_SECOND) / ClockFreq);
-    *elapsed = (((Ticks)r * TICKS_PER_SECOND) / ClockFreq);
+    *user = SecondsToTime(t.tms_utime) / ClockFreq;
+    *elapsed = SecondsToTime(r) / ClockFreq;
 }
 
 #endif // HAVE_TIMES
 
-Ticks getThreadCPUTime(void)
+Time getThreadCPUTime(void)
 {
 #if USE_PAPI
     long long usec;
     if ((usec = PAPI_get_virt_usec()) < 0) {
 	barf("PAPI_get_virt_usec: %lld", usec);
     }
-    return ((usec * TICKS_PER_SECOND) / 1000000);
+    return USToTime(usec);
 
 #elif !defined(BE_CONSERVATIVE) && defined(HAVE_CLOCK_GETTIME) && defined (_SC_THREAD_CPUTIME) && defined(CLOCK_THREAD_CPUTIME_ID) && defined(HAVE_SYSCONF)
     {
@@ -172,8 +169,7 @@ Ticks getThreadCPUTime(void)
             int res;
             res = clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);
             if (res == 0) {
-                return ((Ticks)ts.tv_sec * TICKS_PER_SECOND +
-                        ((Ticks)ts.tv_nsec * TICKS_PER_SECOND) / 1000000000);
+                return SecondsToTime(ts.tv_sec) + NSToTime(ts.tv_nsec);
             }
         }
     }